ABE: Public-Key Cryptography - A Hybrid Approach Using Polybius and Vigenere Cipher

A secure cryptographic system that combines classical ciphers (Polybius and Vigenere) with Ciphertext-Policy Attribute-Based Access Control (CP-ABAC). This system ensures that data is encrypted using a hybrid approach and can only be decrypted by users whose attributes satisfy a specific access policy.

🚀 Project Overview

This project is a full-stack application designed to demonstrate a multi-layered encryption process:

1. Polybius Square Cipher: Initial transformation of the plaintext.
2. Vigenère Cipher: Secondary encryption using a secret key.
3. Attribute-Based Access Control: Implementation of access policies that govern who can decrypt the final ciphertext.

🛠️ Tech Stack

• Frontend: React.js, Vite, Lucide Icons, Vanilla CSS
• Backend: Node.js, Express.js
• Tooling: NPM Workspaces

🚦 Getting Started

Prerequisites

• Node.js (v18 or higher)
• npm (v9 or higher)

Installation

1. Clone the repository:

   git clone <repository-url>
   cd ABE

2. Install dependencies for both frontend and backend from the root:

   npm install

Running the Application

You can run both parts from the root directory using the following scripts:

• Frontend (Dev):

   npm run dev:frontend

• Backend (Dev):

   npm run dev:backend

Frontend API Configuration

The frontend reads backend URL from VITE_API_BASE_URL.

1. Create frontend/.env (or copy from frontend/.env.example)
2. Set:

   VITE_API_BASE_URL=http://localhost:5001

🔐 Cryptography Workflow

1. Plaintext Input: The user provides the message to be encrypted.
2. Policy Definition: An access policy is assigned (e.g., role: "admin", department: "security").
3. Hybrid Encryption:
   • The message is first processed via a Polybius Square.

• The result is then encrypted using the Vigenere Cipher with a user-provided secret key.
• The Vigenere stage transforms printable ASCII data, so special characters in the encrypted stream are also protected.

4. Decryption & Access:
   • A receiver must provide the correct secret key.
   • The receiver's attributes must match the policy embedded in the encryption for successful decryption.